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Q: My koi seem to be gasping for breath at the surface of my pond. Why are they doing this? – Bill in Louisiana

A: If your koi are coming to the surface of the pond to gulp for air, they’re doing more than just saying hi. They’re employing a survival strategy! Due to a lack of aeration or poor water quality, your pond’s water probably does not have enough dissolved oxygen in it for the fish to “breathe,” so they’re gasping for oxygen from the air.

This lack of sufficient oxygen can then cause the fish to stress, which then inhibits their immune systems and opens the door for parasites and disease. But you can prevent that from happening by aerating the water and keeping the water quality as crystal clear as possible.

Koi breathe by pumping water over their gills to extract dissolved oxygen from the pond water. Depending on their activity level, koi require varying amounts of oxygen. For instance, a koi’s active summer metabolism will require more oxygen; a hibernating winter metabolism will require less oxygen.

This can be a challenge during the warm summer months, when the pond’s water temperature rises. Warm water holds less dissolved oxygen, so just when the fish need it the most, it’s at a lower concentration!

To pump more oxygen into the water, you can also add plants to your pond, which naturally release oxygen into the water during the day. Your waterfall or fountain will also add oxygen to your pond. But depending on your fish load and pond size, plants and a fountain often aren’t enough – especially during the summer. That’s where an air diffuser, like the KoiAir™ Water Garden Aeration Kit, can help. Powered by a silent, reliable compressor, a diffuser system will add oxygen to your pond, aerate, circulate and eliminate dead spots, keeping your pond and fish active and healthy all year long.

Because poor water quality can also cause fish to gasp for air at the pond’s surface, you should also check your filtration system, and test your ammonia and nitrite levels with a standard test kit, like the API® Pond Master Test Kit. If your levels are high, consider adding beneficial bacteria, like Pond Logic® LiquidClear™, to kick-start your pond’s nitrogen cycle.

Once you aerate your pond and make sure your water quality is in check, your koi should stop gulping oxygen at the surface. When they do greet you at the water’s edge, it’ll be for a juicy slice of watermelon or some Pond Logic® Floating Ponstix fish food instead!

6 Responses

My pond has a layer of ice on it but there is a good size opening of water my fish are up near the top but under the ice part. I have never seen them do this before
I have to smaller airratiors in the pond
Don’t in need more air.

Hi Evelyn – Unless you actually see them in the open water looking like they are trying to “drink” the air than this is probably not the case. If the fish are moving around and still right side up then they are probably fine.

Hi Kate thanks for the reply yes the fish are moving and right side up this far. Just a little odd they are all near the top under the ice on the shelf of the pond however I did put another airratior in the pond and it didn’t seem to make a difference.

Thanks. I spend a lot of time reading all I can. This is very helpful to know what I’m thinking is hopefully right or gets me to the right answer. I have koi fish ,and one is about 14 to 16 inches now, in a tank of 75 gallon,and other small ones, I see that there is no end to the growing process, this fish has taken me from a 30 toa75 gallon tank, next is a pond, I hate to see my baby go ,